As a method for treating cancer, there have been surgical resection, radiotherapy and chemotherapy using an anti-tumor agent. In recent years, other than these methods, various therapeutic methods have been studied and put into practice. One of them is an immuno-cell therapy utilizing immunocytes.
The immuno-cell therapy includes a LAK (Lymphokine Activated Killer) therapy in which lymphocytes are activated in vitro by lymphokine and then transferred into the body, a CTL (Cytotoxic T Lymphocyte; hereinafter, referred to as CTL) therapy using CTLs that recognize and injure a lesion specifically, a dendritic cell therapy and the like.
In the dendritic cell therapy, using dendritic cells obtained by allowing a disease antigen to be present on MHC (Major Histocompatibility antigen Complex) directly or after intracellular processing, disease antigen-specific CTLs that attack a pathogen selectively are induced in vivo for treatment. The disease antigen to be presented can be, for example, a cancer antigenic protein or peptide, an infectious disease antigenic protein or peptide, or a part thereof (see Non-patent documents 1 and 2, for example).
By co-culturing the dendritic cells pulsed with the disease antigen and lymphocytes so as to stimulate the lymphocytes with the dendritic cells, it is possible to induce disease antigen-specific CTLs in vitro. For example, in the case of using the dendritic cells pulsed with the cancer antigenic protein or peptide or the infectious disease antigenic protein or peptide, an increase in the disease antigen-specific CTLs induced at a co-culture is 5 to 20 times as much as that in the case where the above-noted dendritic cells are not used.
In the dendritic cell therapy using the dendritic cells pulsed with the cancer antigenic protein or peptide or the infectious disease antigenic protein or peptide, the efficiency of induction of the disease antigen-specific CTLs in vivo, namely, the ratio of the CTLs in all the lymphocytes is known to rise by a factor of 2 to 14.
In order to enhance the efficacy of the dendritic cell therapy by raising the efficiency of induction of the disease antigen-specific CTLs by dendritic cells, two methods mainly are conducted at present.
In one method, in addition to pulsing the dendritic cells with the disease antigen, by allowing a drug or the like that reacts with a Toll like receptor (hereinafter, referred to as TLR) on the dendritic cells to react with the dendritic cells so as to enhance an antigen-presenting ability of the dendritic cells, the efficiency of induction of the disease antigen-specific CTLs directly increases (an adjuvant effect via the TLR; see Non-patent documents 3 and 4, for example). In the other method, in addition to pulsing the dendritic cells with the disease antigen, by allowing glycolipid or the like to be present on antigen-presenting molecules other than MHC molecules, for example, CD1d (Cluster Differentiation 1d) molecules on the dendritic cells so as to activate immunocytes including iNKT (invariant Natural Killer T cells), etc. other than the disease antigen-specific CTLs, so that the efficiency of induction of the disease antigen-specific CTLs indirectly increases via these activated immunocytes (an adjuvant effect via the immunocytes other than the disease antigen-specific CTLs; see Non-patent documents 5 and 6, for example).
However, the increase in the disease antigen-specific CTL induction by the direct adjuvant effect via the TLR or the indirect adjuvant effect via the immunocytes other than the disease antigen-specific CTLs is about 4 to 6 times that in the case where these adjuvants are not used (in vitro). Accordingly, it has been desired to develop the technology capable of inducing the disease antigen-specific CTLs more efficiently.    Non-patent document 1: Blood 2004, 103, 383-389    Non-patent document 2: Proc Natl Acad Sci U.S.A. 2001, 98, 8809-8814    Non-patent document 3: Nat Rev Immunol. 2004, 4, 449-511    Non-patent document 4: Cancer Res. 2004, 64, 5461-5470    Non-patent document 5: J Clin Invest. 2004, 114, 1800-1811    Non-patent document 6: J Exp Med. 2002, 195, 617-624
The present invention was made with the foregoing in mind and provides a method for activation treatment of an antigen-presenting cell (for example, a dendritic cell or the like) for efficiently inducing an immunocyte that dominantly includes a disease antigen-specific CD8+ CTL and/or a γδ T cell in vivo and/or in vitro, a medical composition comprising the activated antigen-presenting cell, a treatment and prevention method using the activated antigen-presenting cell, an induction method of an immunocyte that includes a disease antigen-specific CD8+ CTL and/or a γδ T cell using the activated antigen-presenting cell, an immunocyte that is induced by the method, a medical composition comprising the immunocyte, and a treatment and prevention method using the immunocyte.
In order to solve the problem described above, the inventors of the present invention conducted studies. Then, the inventors found that, by co-pulsing dendritic cells with bisphosphonate in addition to the pulse with a disease antigen, the ratios of disease antigen-specific CTLs and γδ T cells to all lymphocytes and the numbers of the disease antigen-specific CTLs and the γδ T cells increased considerably compared with the case of adding no bisphosphonate, and they completed the present invention. For example, by adding bisphosphonate, the ratio of the disease antigen-specific CTLs to all the lymphocytes can increase by a factor of about 100 and the ratio of the γδ T cells to all the lymphocytes can increase by a factor of about 3 compared with those in the case of adding no bisphosphonate, and the number of the disease antigen-specific CTLs can increase by a factor of about 90 and the number of the γδ T cells can increase by a factor of about 6 compared with those in the case of adding no bisphosphonate. However, the present invention is not limited to these numerical values. The present invention promotes further development of the immuno-cell therapy that treats and prevents cancer and/or infectious disease by inducing disease antigen-specific CD8+ CTLs and/or γδ T cells.